(a) Technical Field
The present disclosure relates to a fuel cell system and a driving control method thereof, and more particularly, to a fuel cell system and a driving control method thereof capable of improving drivability of a vehicle and durability of a fuel cell.
(b) Background Art
Generally, a fuel cell vehicle includes a fuel cell stack in which a plurality of fuel cells used as a power source is stacked. A fuel supply system supplies hydrogen and the like as fuel to the fuel cell stack. An air supply system supplies oxygen necessary for an electro-chemical reaction as an oxidizing agent. Water and heat management system controls a temperature of the fuel cell stack.
The fuel supply system depressurizes compressed hydrogen in a hydrogen tank and supplies it to an anode of the fuel cell stack. An air supply system supplies inhaled external air to a cathode of the fuel cell stack by operating an air blower.
When hydrogen is supplied to the anode of the fuel cell stack, and oxygen is supplied to the cathode thereof, hydrogen ions are separated through a catalytic reaction in the anode, and the separated hydrogen ions are transferred to the cathode as an oxidation electrode through an electrolytic film. Here, the hydrogen ions separated from the anode, electrodes, and oxygen electro-chemically react together in the oxidation electrode to produce electricity. In more detail, hydrogen is electro-chemically oxidized in the anode, and oxygen is electro-chemically reduced in the cathode. Electricity and heat are generated through movement of electrons produced at that time, and water vapor or water is generated through a chemical reaction where hydrogen and oxygen are combined.
An exhausting device is provided for discharging by-products, such as, water vapor, water, and heat, which are produced as the electricity is generated through the fuel cell stack and not-reacted on hydrogen, oxygen, etc. The gases, such as, water vapor, hydrogen, oxygen, and the like are exhausted to the outside through a discharging passage.
Configurations of the air blower, a hydrogen reflow blower, a water pump, and the like for driving a fuel cell are coupled to a main bus terminal to easily start the fuel cell. Various relays for blocking and connecting electrical power and a diode for preventing reverse-current to the fuel cell may be connected to the main bus terminal.
Dry air supplied through the air blower is humidified through a humidifier and then supplied to the cathode of the fuel cell stack. The discharging gas from the cathode is transferred to the humidifier while it is humidified through water produced inside the fuel cell stack, and may be used when humidifying the dry air to be supplied to the cathode by the air blower.
Fuel cell stop or fuel cell restart, where power generation of the fuel cell stops and restarts when necessary to improve fuel efficiency is an idle stop and on/off control where the power generation of the fuel cell temporally stops in the fuel cell vehicle, is considered to be important.
Specifically, when stopping and restarting the power generation of the fuel cell while the vehicle is running, stopping and restarting of the fuel cell need to be controlled, considering the occurrence of dry out in the fuel cell stack, re-acceleration, fuel efficiency, etc.
The description provided above as related art of the present disclosure is just for helping in understanding the background of the present disclosure and should not be construed as being included in the related art known by those skilled in the art.